This reverts commit ecd50f714c421c759354632dd00f70c718c95b10
since it causes build errors with CONFIG_CONTEXT_TRACKING and
that has been made from misunderstandings; context_track_user_*()
don't involve much in interrupt context, it just returns
if in_interrupt() is true.
Instead of changing the do_debug/int3(), this just adds
context_track_user_*() to kprobes blacklist, since those are
still can be called right before kprobes handles int3 and debug
exceptions, and probing those will cause infinit loop.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Reported-by: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Rusty Russell <ru...@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.agu...@hds.com>
---
arch/x86/kernel/traps.c | 7 ++++---
kernel/context_tracking.c | 3 +++
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index c6eb418..0d0e922 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -343,6 +343,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs,
long error_code)
if (poke_int3_handler(regs))
return;
+ prev_state = exception_enter();
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
@@ -351,9 +352,8 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs,
long error_code)
#ifdef CONFIG_KPROBES
if (kprobe_int3_handler(regs))
- return;
+ goto exit;
#endif
- prev_state = exception_enter();
if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
@@ -433,6 +433,8 @@ dotraplinkage void do_debug(struct pt_regs *regs, long
error_code)
unsigned long dr6;
int si_code;
+ prev_state = exception_enter();
+
get_debugreg(dr6, 6);
/* Filter out all the reserved bits which are preset to 1 */
@@ -465,7 +467,6 @@ dotraplinkage void do_debug(struct pt_regs *regs, long
error_code)
if (kprobe_debug_handler(regs))
goto exit;
#endif
- prev_state = exception_enter();
if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
SIGTRAP) == NOTIFY_STOP)
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 019d450..5664985 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -19,6 +19,7 @@
#include <linux/sched.h>
#include <linux/hardirq.h>
#include <linux/export.h>
+#include <linux/kprobes.h>
#define CREATE_TRACE_POINTS
#include <trace/events/context_tracking.h>
@@ -104,6 +105,7 @@ void context_tracking_user_enter(void)
}
local_irq_restore(flags);
}
+NOKPROBE_SYMBOL(context_tracking_user_enter);
#ifdef CONFIG_PREEMPT
/**
@@ -181,6 +183,7 @@ void context_tracking_user_exit(void)
}
local_irq_restore(flags);
}
+NOKPROBE_SYMBOL(context_tracking_user_exit);
/**
* __context_tracking_task_switch - context switch the syscall callbacks
--
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